Rule.



c- UNITED STATES Patented J une 6, 1905.

PATENTV OFFICE.

OF ONE-HALF To ADOLPH J; E.

SYLVANIA.

KOPOKE, OF LANCASTER, PENN- Y SPECIFICATION forming part of Letters Patent No. 791,848, dated J une 6, 1905.

T0 all whom it may concern: Be it known that I, JOHN ELwooD WILSON, a citizen of the United States, and a resident of Lancaster, in the county of Lancaster and` State of Pennsylvania, have invented a new and Improved Rule, of which the following is a full, clear, and exactvdescription.

My invention relates to a rule; and the ob' jects thereof are to provide means for calculating distances and angles. The rule is capable of general use;` but it is especially applicable for buildingv purposes.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters ofreference indicate corresponding parts in all the figures.

Figure l is a plan view of a preferred form of my invention, showing the parts in operative position. Fig. Q is a fragmentary View showing a portion of the device on a large scale. Fig. 3 is a sectional view on the line 3 3 of Fig. 2. Fig. 4 is a rear view of the parts or blades shown in Fig. 2; and Fig. 5 is a view of the entire device, showing it closed up.

In the drawings the rule is shown as composed of three parts a?) c. These parts are preferably made exactly alike; but, if desired, modifications may be made in any of them without changing the others. They are preferably provided with circular enlargements at one end. The enlargements Z2' and c of the parts and c are shown in the drawings. The corresponding circular enlargement on the part a is not illustrated in the drawings. These circular enlargements are provided with centers exactly in line with the inner edge of each rule or the blade thereof and are provided with protractors b2 c2 concentric with the above-mentioned centers.

The two parts a and 5 are preferably connected together by means of a slide d, which 1 is usually bent around the body of the part a,

being provided with flanges cl for the purpose of holding it in position/and permitting it to slide along the main blade a. The blade I; is mounted upon this slide by means of a thumb-screw e, concentric with the protractor b2 and so placed that its center will be coincident with the line passing along the inner edge of the blade a. The blades c and c are t l Application filed July 9, 1904. Serial No. 215,855.

,connected together by a similar thumb-screw e, so that the two inner edges will meet at the pivotalpoint.

blade a for use in reading the protractor c2, so as to iind the angle at which the blade c is 'set with respect to the blade a. In the same manner .a notch or projection g is provided on the slide Z for the purpose of reading the protractor 52. It will be Observed that by putting the slide at the extreme end of the blade a, the blades I) and c may be folded together, as shown in Fig. 5, the blade c covering the blade a. Furthermore, it will also Ibe obvious thatthe slide UZ may be set at any desired point upon the blade a andlthe other two blades extended in a line with the blade a, so that the fdevice can be used as a measuring instrument for lengths up to the combined length of the three blades.

Although I have illustrated a particular embodiment of my invention, it will be obvious that the latter Vis not strictly limited thereto and that other forms may be used without departing from the spirit of the invention.

the work demands it, and any sort of a scale may be employed on the blades. The one which I prefer to use, however, is that known as the carpenters scale, in which the inches are divided in twelfths, so that for purposes of calculation they may be regarded as feet and conveniently represent the inches also. This rule can be used in all kinds of framing andfor calculating the various parts of triangles of all kinds.

One manner of using the device will be obvious from Fig. 1. The blade b may be set at half the width of a building, and the blade c being placed at the desired pitch would give the cut and length of a rafter. In the same way lengths of rails and height of rise on Astairways may be obtained by setting the blade at the desired length of the stairs and setting the blade c so that it will intersect with the blade Z1 at a point indicating the desired height. The pitch and length of rake may then be obtained and read directly from the device.

The device may also be used for other forms A mark f is formed upon the edge of they IOO 75 More than three blades may be employed if of triangles and for figuring the lengths and cuts oi' braces for trusses and the like. It is to be understood, however, that the shorter edges or inside edges, as they have been called, are the'ones upon which the readings are to be taken, for the reason that the centers of the circular extensions are allin line With these edges. The blades may be reversed from the positions shown, if desired. The blade c, for example, may be turned over to make the working edges come on the inside. Then all of the working edges would be together and form a complete triangle.

Having thus described my invention, I claim as new and desire to secure by Letters Patent l. The combination of a main blade having a circular end scaled to constitute a protractor, a second scaled blade having a circular end, said blades being pivoted together at the centers of said circular ends, and a third scaled blade having a circular end scaled to constitute a protractor movably and pivotallT mounted on the first blade, the center of the last-named circular end being located on a line coincident with the edge of the main blade, and each of said blades being of the same size and shape as, and interchangeable with, the others.

2. The combination of a main blade having a circular end scaled to constitute a protractor, a second scaled blade having a circular end, said blades being pivoted together at the centers of said circular ends and each free to describe a complete circle about their pivot, and a third scaled blade having a circular end scaled to constitute a protractor movably and pivotally mounted on the first blade and free to describe a complete circle about its pivot, the center of the last-named circular end being located on aline coincident with the edge of the main blade, the circular ends oi' said blades being of the same size and each blade being interchangeable with the other.

3. The combination of a main blade having a circular end scaled to constitute a protractor, a second scaled blade having a circular end, said blades being pivoted together at the centers of said circular ends, and a third scaled blade having a circular end scaled to constitute a protractor movably and pivotally mounted on the first blade, the center of the last-named circular end being located on a line coincident with the edge of the main blade and each of said blades being a counterpart of the others, said second and third blades being movable on the main blade independently of each other and each blade being interchangeable with one of the others.

4. The combination of a main blade having a circular end scaled to constitute a protractor, a second scaled blade having a circular end, said blades being pivoted together at the centers of said circular ends, a third scaled blade having a circular end scaled to constitute a protractor movably and pivotally mounted on the lirst blade, the center ol the last-named circular end being located on a line coincident with the edge ot' the main blade and each of said blades being a counterpart of the others, said second and third blades being movable on the main blade independently of each other, a slide ior connecting the third blade with the lirst one, said slide comprising a piece of sheet metal bent upon itselfl and adapted to inclose thc main blade, and a clamping device passing through both parts of said slide and engaging the third blade at the center of its circular end, said slide also being provided with a mark for registering with the protractor on said third circular end.

In testimony whereof I have signed mynalne to this specification in the presence of two su bscribing witnesses.

JOHN ELlVOOD VILSON.

Witnesses:

N. STEINWANDEL 'A. F. SHENCK. 

